A drilling motor with a bent housing is usually used in directional drilling. When the drilling motor has fluid pumped through it to provide rotation to the bit and the drill string and drilling motor is stationary, the drilled well bore follows a generally curved path in the direction of the bent housing. When the drilling motor has fluid pumped through it to provide rotation to the bit and the drill string and drilling motor is rotated, the drilled well bore follows a generally straight path due to the rotation of the bent housing.
The combination of the curved and straight path segments allows the directional control of a well bore to follow a predetermined course.